.group_info_simple {
    display: flex;
    flex-direction: column; 
    align-items: center;
    justify-content: center;
    width: 280px;
    padding: 24px;
    background-color: #333f44;
    color: #fff;
}
.group_info_group_avator_wrapper {
    position: relative;
    cursor: pointer;
    user-select: none;
}
.group_info_group_avator_wrapper:hover .avator_upload_mask{
    opacity: 1;
}
.group_info_group_avator {
    border: 2px solid #fff;
}
.avator_upload_mask {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    width: 100px;
    height: 100px;
    line-height: 100px;
    background-color: rgba(0,0,0,.4);
    border-radius: 50%;
    text-align: center;
    color: #fff;
    opacity: 0;
}
.group_info_group_id {
    font-size: 16px;
}
.group_info_group_name {
    margin-top: 20px;
    font-size: 24px;
}
.join_btn {
    margin-top: 60px;
    height: 40px;
}
.join_btn button {
    height: 40px;
    padding: 8px 12px;
    color: #000;
    background-color: rgba(255, 255, 255, .8);
}
.join_btn button:hover {
    background-color: rgba(255, 255, 255, 1);
}